Catalytic converters are commonly installed in road vehicles and airplanes to control exhaust gas emissions by converting toxic gases to less toxic pollutants using accelerated (catalytic) chemical reactions. Once the catalytic activity of the converter deteriorates or has been damaged as a result of accident or for any other reason, the converter can be recycled. Catalytic converter recycling has been around since the 1970's and the industry still flourishes today.
The current way to process spent or damaged catalytic converters is through the use of equipment to slice or shear the outer metallic or ceramic housing of the converter. The shears are usually guillotine and alligator types, which pose great occupational risk to workers in the industry. Additionally, the process is usually carried out in open-aired rooms, with or without limited fume extractors (vacuums), thereby exposing workers and the facility to toxic dust and fumes that are generated during the recycling process.
After the housing is cut and removed, this provides access to the inner support material, which acts a carrier for the catalytic agents. These agents typically employ precious group metals such as platinum, palladium, and rhodium. The carrier can be of two types: ceramic or metal sheet (foil-like). Both types of carriers have a washcoat applied to the precious metals. There are several ways to recover the precious metals. One such method is U.S. Pat. No. 5,279,464. This scheme mechanically comminutes the entire catalytic converter into particles to form a mixture comprising fractions of the metallic housing, the carrier, and the catalyst. These fractions are then segregated on the basis of different characteristics using pneumatic classifiers, magnetic separators, and filters. The scheme is specifically designed for recycling catalytic converters with metallic or foil carriers, commonly known as metallic converters.
The present invention does not involve comminuting or grinding the entire metallic converter. It does not require pneumatic or magnetic separation. Additionally, it can be used for recycling ceramic converters.